Amateur Radio (Ham Radio)
The full technical guide to ham radio: frequency bands, modulation modes, protocols, equipment, and how to actually communicate.
License Classes & Privileges
US amateur radio operators are licensed by the FCC under 47 CFR Part 97. Three license classes exist, each granting progressively wider frequency privileges. No Morse code test is required for any class (eliminated 2007). All exams are 35 multiple-choice questions from a question pool; passing score is 74% (26 correct).
Technician Class (TCL)
Entry-level license. Privileges span VHF/UHF with full privileges on all bands above 50 MHz, plus limited HF access. Technician class holders can operate:
- VHF: 144–148 MHz (all modes, up to 1500 W PEP)
- UHF: 420–450 MHz (all modes, up to 1500 W PEP)
- 6m: 50–54 MHz (full privileges — the "Magic Band")
- 2m: 144–148 MHz (FM simplex, repeaters, SSB weak-signal, satellite)
- 70cm: 420–450 MHz (FM, digital modes, satellite, ATV)
- 1.25m: 222–225 MHz (all modes)
- HF (limited): 28.0–28.5 MHz CW/SSB only, 28.5–29.7 MHz FM phone, 50 W max
Technician privileges were expanded in 2017 to include phone (SSB) on 80m, 40m, and 15m on a secondary basis at 200 W PEP or less, though most Technicians focus on VHF/UHF operations and repeater networks.
General Class (GEN)
Intermediate license granting access to all HF bands with full VHF/UHF privileges. General class operators can use:
- All HF bands: 160m through 10m (1.8–29.7 MHz)
- Full power: Up to 1500 W PEP on all bands
- All sub-bands: Full access to all amateur frequency allocations
- Digital modes: RTTY, PSK31, FT8, packet, etc. on all bands
- All VHF/UHF: Same as Technician plus all sub-bands
The General class is the "sweet spot" for HF DXing — it grants access to the most productive HF bands (20m, 40m, 15m, etc.) where worldwide communication via ionospheric propagation is routine.
Amateur Extra Class (AE)
Highest US license class. Grants full privileges on all amateur bands with no restrictions. Extras get exclusive operating segments on several bands that General class operators cannot access:
- 80m CW segment: 3.5–3.6 MHz (Extra only below 3.525 MHz)
- 40m CW segment: 7.0–7.125 MHz (Extras only below 7.050 MHz)
- 20m CW segment: 14.0–14.15 MHz (Extras only below 14.025 MHz)
- 15m segment: 21.0–21.45 MHz (Extras only below 21.050 MHz for CW)
- 10m segment: 28.0–29.7 MHz (full access)
- All VHF/UHF: Complete access including exclusives
The Extra class is required for contesting on many HF bands and for operating as a control operator at club stations. It also signifies deep knowledge of radio theory, regulations, and operating practices.
Complete HF Band Plan
The IARU Region 2 (Americas) band plan divides HF amateur allocations into segments by mode. The FCC Part 97 defines the legal boundaries; the ARRL publishes voluntary band plans with recommended operating segments.
╔══════════════════════════════════════════════════════════════════════════════╗ ║ IARU REGION 2 HF BAND PLAN (AMERICAS) ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 160 METERS (1.8-2.0 MHz) — "Top Band" — Nighttime DX only ║ ║ ───────────────────────────────────────────────────────── ║ ║ 1.800-1.840 MHz │ CW │ Beacons, DX calling (1.810 kHz DX) ║ ║ 1.840-1.850 MHz │ Digital │ FT8, JS8Call, WSPR ║ ║ 1.843-2.000 MHz │ SSB/Phone │ DX calling 1.843 MHz (QRP 1.805 MHz) ║ ║ 1.900-2.000 MHz │ SSB/Phone │ Regional net frequencies ║ ║ Notes: Extremely challenging band. Atmospheric noise is high. ║ ║ Requires large antennas (160m λ/4 = 130 ft). Night only. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 80 METERS (3.5-4.0 MHz) — Regional day, DX night ║ ║ ────────────────────────────────────────────── ║ ║ 3.500-3.600 MHz │ CW │ DX, contesting (3.535 kHz QRP) ║ ║ 3.600-3.650 MHz │ Digital │ FT8, RTTY, PSK31, JS8Call ║ ║ 3.650-4.000 MHz │ SSB/Phone │ Calling frequency 3.845 MHz ║ ║ 3.985-4.000 MHz │ SSB/Phone │ NTSC/emergency nets ║ ║ Notes: Regional band. 150W PEP on sub-bands below 3.6 MHz for Generals. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 60 METERS (5 MHz) — 5 CHANNELS ONLY — Primary ARES emergency band ║ ║ ────────────────────────────────────────────────────────────── ║ ║ 5.3305 MHz │ USB │ 2.8 kHz BW max │ 100W ERP max │ Primary channel ║ ║ 5.3465 MHz │ USB │ 2.8 kHz BW max │ 100W ERP max │ Alt channel ║ ║ 5.3570 MHz │ USB │ 2.8 kHz BW max │ 100W ERP max │ Alt channel ║ ║ 5.3715 MHz │ USB │ 2.8 kHz BW max │ 100W ERP max │ Alt channel ║ ║ 5.4035 MHz │ USB │ 2.8 kHz BW max │ 100W ERP max │ Alt channel ║ ║ Notes: Channelized — no operation between channels. USB only. ║ ║ 100W ERP (Effective Radiated Power). ARISS emergency backup. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 40 METERS (7.0-7.3 MHz) — Best all-around HF band ║ ║ ────────────────────────────────────────────────── ║ ║ 7.000-7.125 MHz │ CW │ DX, contesting (7.030 kHz QRP) ║ ║ 7.125-7.300 MHz │ SSB/Phone │ Calling frequency 7.200 MHz ║ ║ 7.040-7.050 MHz │ Digital │ FT8 calling frequency ║ ║ 7.070-7.100 MHz │ Digital │ PSK31, RTTY ║ ║ Notes: Regional during day, worldwide at night. Most useful band. ║ ║ NVIS-capable for regional coverage on lower frequencies. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 30 METERS (10.1-10.15 MHz) — CW/DIGITAL ONLY — 150W PEP ║ ║ ──────────────────────────────────────────────────────── ║ ║ 10.100-10.150 MHz │ CW/Digital │ No phone! Max 150W PEP ║ ║ 10.106-10.140 MHz │ │ RTTY, FT8, PSK31, Packet ║ ║ Notes: Shared with government/military. Non-exclusive secondary. ║ ║ No phone operations permitted. 150W PEP maximum. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 20 METERS (14.0-14.35 MHz) — THE DX BAND ║ ║ ────────────────────────────────────────── ║ ║ 14.000-14.150 MHz │ CW │ DX, contesting (14.030 kHz QRP) ║ ║ 14.150-14.350 MHz │ SSB/Phone │ Calling frequency 14.200 MHz ║ ║ 14.060-14.070 MHz │ Digital │ FT8 calling frequency ║ ║ 14.070-14.100 MHz │ Digital │ PSK31, RTTY, other modes ║ ║ Notes: The premier DX band. Open year-round during daytime. ║ ║ Propagates worldwide even at solar minimum. SSB is dominant. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 17 METERS (18.068-18.168 MHz) — 100 kHz slice ║ ║ ─────────────────────────────────────────────── ║ ║ 18.068-18.100 MHz │ CW │ DX calling (18.095 MHz QRP) ║ ║ 18.100-18.168 MHz │ SSB/Phone │ Calling frequency 18.130 MHz ║ ║ Notes: Excellent DX band, less crowded than 20m. Good during moderate ║ ║ solar conditions. Narrow allocation but productive. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 15 METERS (21.0-21.45 MHz) — SOLAR MAX BAND ║ ║ ────────────────────────────────────────── ║ ║ 21.000-21.050 MHz │ CW │ DX, contesting (21.030 kHz QRP) ║ ║ 21.050-21.450 MHz │ SSB/Phone │ Calling frequency 21.200 MHz ║ ║ 21.060-21.070 MHz │ Digital │ FT8 calling frequency ║ ║ 21.070-21.100 MHz │ Digital │ PSK31, RTTY ║ ║ Notes: Excellent worldwide DX during solar maximum. Often dead at solar ║ ║ minimum. Supports long-path propagation to Asia/Australia. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 12 METERS (24.89-24.99 MHz) — 100 kHz slice ║ ║ ───────────────────────────────────────────── ║ ║ 24.890-24.940 MHz │ CW │ DX calling (24.906 MHz QRP) ║ ║ 24.940-24.990 MHz │ SSB/Phone │ Calling frequency 24.950 MHz ║ ║ Notes: Small band, often overlooked. Good for DX when 10m is marginal. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 10 METERS (28.0-29.7 MHz) — THE BIG BAND ║ ║ ────────────────────────────────────────── ║ ║ 28.000-28.300 MHz │ CW │ DX, contesting (28.030 kHz QRP) ║ ║ 28.300-29.700 MHz │ SSB/Phone │ Calling frequency 28.400 MHz ║ ║ 28.060-28.070 MHz │ Digital │ FT8 calling frequency ║ ║ 28.070-28.120 MHz │ Digital │ PSK31, RTTY, other modes ║ ║ 29.600 MHz │ FM simplex│ Calling frequency — narrow FM ║ ║ 29.000-29.200 MHz │ SSB │ SSB calling 29.020 MHz ║ ║ 29.300-29.500 MHz │ FM relay │ Repeater outputs (10m repeaters) ║ ║ Notes: Opens worldwide during solar maximum. Technicians get 28.3-29.7 ║ ║ MHz phone (FM on 29.6 MHz). First band to go, last to return. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
VHF/UHF Bands
Above 50 MHz, amateur radio shifts from skywave propagation to line-of-sight, with occasional enhanced propagation modes. These bands are where most local repeater activity occurs.
╔══════════════════════════════════════════════════════════════════════════════╗ ║ VHF/UHF AMATEUR BAND PLAN ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 6 METERS (50-54 MHz) — "THE MAGIC BAND" ║ ║ ────────────────────────────────────────── ║ ║ 50.000-50.100 MHz │ CW/Beacons │ Weak-signal DX, beacon testing ║ ║ 50.100-50.125 MHz │ SSB │ DX calling frequency 50.125 MHz ║ ║ 50.125-50.300 MHz │ SSB │ General SSB operating ║ ║ 50.300-50.600 MHz │ Digital │ FT8, packet, other modes ║ ║ 50.600-50.800 MHz │ SSB │ Non-contest SSB ║ ║ 51.000-51.100 MHz │ FM Repeater│ Input frequencies ║ ║ 51.100-51.300 MHz │ FM Repeater│ Output frequencies (1 MHz split) ║ ║ 51.300-51.500 MHz │ FM Simplex │ 12.5/25 kHz channels ║ ║ 51.500-53.000 MHz │ FM Repeater│ Extended repeater sub-band ║ ║ 53.000-54.000 MHz │ TV/ATV │ Analog television, ATV ║ ║ Notes: Sporadic-E propagation allows 1000+ mile contacts when conditions ║ ║ are right. "Magic band" because openings are unpredictable. ║ ║ λ/2 dipole = 9 ft 10 in. 1/4 wave vertical = 4 ft 11 in. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 2 METERS (144-148 MHz) — MOST POPULAR VHF BAND ║ ║ ────────────────────────────────────────────── ║ ║ 144.000-144.100 MHz │ CW/Beacons│ Weak-signal DX, EME, meteor scatter ║ ║ 144.100-144.200 MHz │ SSB │ SSB calling frequency 144.200 MHz ║ ║ 144.200-144.300 MHz │ SSB │ General SSB operating ║ ║ 144.300-144.500 MHz │ SSB │ Additional SSB ║ ║ 144.500-144.600 MHz │ Digital │ Packet, APRS ║ ║ 144.600-144.900 MHz │ Digital │ Various digital modes ║ ║ 144.900-145.100 MHz │ FM Repeater│ Standard repeater outputs ║ ║ 145.100-145.200 MHz │ FM Repeater│ Additional repeaters ║ ║ 145.200-145.500 MHz │ FM Simplex│ Simplex operation ║ ║ 145.500-145.800 MHz │ FM Simplex│ National calling 145.500 MHz (FM) ║ ║ 145.800-146.000 MHz │ Satellites│ Satellite uplink/downlink ║ ║ 146.010-146.370 MHz │ FM Repeater│ Repeater inputs (600 kHz offset) ║ ║ 146.400-146.580 MHz │ FM Simplex│ General FM simplex ║ ║ 146.520 MHz │ FM │ NATIONAL CALLING FREQUENCY (FM) ║ ║ 146.580-146.995 MHz │ FM Repeater│ Repeater outputs (600 kHz offset) ║ ║ 147.000-147.395 MHz │ FM Repeater│ Repeater outputs (600 kHz offset) ║ ║ 147.600-147.995 MHz │ FM Repeater│ Repeater outputs (600 kHz offset) ║ ║ Notes: The workhorse band. λ/2 dipole = 3 ft 8 in. Repeater coverage ║ ║ extends range via "machine" relay on mountaintops/buildings. ║ ║ Repeater output 146.610-146.970 MHz covers most major markets. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 1.25 METERS (222-225 MHz) — "POCKET BAND" ║ ║ ──────────────────────────────────────────── ║ ║ 222.000-222.150 MHz │ CW │ CW only ║ ║ 222.100-223.900 MHz │ SSB │ SSB, CW, digital ║ ║ 223.500-225.000 MHz │ FM Repeater│ FM repeaters, simplex ║ ║ Notes: Often overlooked, less congested than 2m/70cm. Good repeater ║ ║ band. Requires General+ (Technician limited to 222.1-223.9 MHz). ║ ║ λ/4 vertical = 1 ft 3.5 in. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 70 CENTIMETERS (420-450 MHz) — PRIMARY UHF BAND ║ ║ ──────────────────────────────────────────────── ║ ║ 420.000-426.000 MHz │ CW/Beacons│ Weak-signal, beacons ║ ║ 426.000-432.000 MHz │ SSB │ Weak-signal SSB, EME ║ ║ 432.000-435.000 MHz │ SSB/Digit.│ SSB, FT8, PSK31, APRS ║ ║ 435.000-438.000 MHz │ Satellite │ Satellite downlinks (SO-50, AO-91, etc.) ║ ║ 440.000-445.000 MHz │ FM Repeater│ Repeater outputs (5 MHz offset) ║ ║ 445.000-446.000 MHz │ FM Simplex│ GMRS-adjacent simplex ║ ║ 446.000-450.000 MHz │ FM Repeater│ Repeater outputs ║ ║ Notes: Smaller wavelength = more gain from same-size antennas. ║ ║ Good for dense urban areas. 440 MHz repeaters are common. ║ ║ λ/4 vertical = 2.6 in. 19-element Yagi = practical. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 33 CENTIMETERS (902-928 MHz) — MICROWAVE-ADJACENT ║ ║ ─────────────────────────────────────────────────── ║ ║ 902.000-906.000 MHz │ CW/Beacons│ Weak-signal ║ ║ 906.000-915.000 MHz │ SSB/Digit.│ SSB, FT8, digital modes ║ ║ 915.000-926.000 MHz │ FM/Digit. │ FM simplex, repeaters, digital ║ ║ Notes: Shared with ISM band (902-928 MHz). Increasingly used for IoT. ║ ║ Higher noise floor. 900 MHz wireless phones share this band. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ 23 CENTIMETERS (1240-1300 MHz) — MICROWAVE ENTRY ║ ║ ──────────────────────────────────────────────────── ║ ║ 1240.0-1260.0 MHz │ CW/Beacons│ Weak-signal, beacons ║ ║ 1260.0-1270.0 MHz │ Satellite │ Satellite uplinks ║ ║ 1270.0-1280.0 MHz │ Digital │ D-STAR, DMR, digital modes ║ ║ 1280.0-1290.0 MHz │ FM │ FM simplex, repeaters ║ ║ 1290.0-1300.0 MHz │ EME/Micro.│ EME, experimental, amateur TV ║ ║ Notes: First true microwave amateur band. Small antennas = high gain. ║ ║ λ/2 dipole = 4.7 in. Good for dish-fed EME experiments. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
Modulation Modes — Technical Reference
Amateur radio uses a wide range of modulation modes, from the simplest CW (Morse code) to advanced digital protocols that decode below the noise floor. Each mode has specific bandwidth, emission designator, and optimal use case.
Analog Voice Modes
╔══════════════════════════════════════════════════════════════════════════════╗ ║ ANALOG MODULATION MODES ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ CW (Continuous Wave) — Morse Code ║ ║ ───────────────────────────────── ║ ║ Bandwidth: 150-300 Hz (tightest of any mode) ║ ║ Emission: A1A (unmodulated carrier, keying only) ║ ║ Speed: 5-25+ WPM (5 WPM slow, 20+ WPM contesting) ║ ║ Bandwidth: ~150 Hz at 5 WPM, ~300 Hz at 25 WPM ║ ║ Power advantage: ~10 dB over SSB (narrow BW = less noise) ║ ║ Keying: Full break-in (QSK) or semi break-in ║ ║ Fists: Straight key, paddle + iambic keyer, bug, electronic ║ ║ Filter: 250-500 Hz CW filter recommended for SDR rigs ║ ║ Best for: DX, weak-signal, low power, emergency, contests ║ ║ Calling freqs: 1.810, 3.535, 7.030, 10.106, 14.030, 21.030, 28.030 ║ ║ Notes: Most power-efficient mode. QRP = 5W or less. ║ ║ Skilled ops copy 40+ WPM in noise. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ SSB (Single Sideband) — Voice ║ ║ ──────────────────────────────── ║ ║ Bandwidth: 2.4-2.8 kHz (standard phone) ║ ║ Emission: J3E (suppressed carrier, single sideband) ║ ║ Sideband: USB above 10 MHz, LSB below 10 MHz ║ ║ Carrier: Suppressed 40-50 dB below peak envelope ║ ║ PEP output: Standard 100W, legal limit 1500W PEP ║ ║ Microphone: Desktop (Heil, Yaesu), headset, boom ║ ║ Processing: speech processor, compressor (5:1 typical) ║ ║ ALC: Keep ALC in green; avoid flat-topping ║ ║ Filter: 1.8-2.4 kHz SSB filter (narrow = less QRM) ║ ║ Best for: DX ragchews, nets, DX calling, emergency comms ║ ║ Calling freqs: 1.843, 3.845, 7.200, 14.200, 21.200, 28.400 ║ ║ Notes: USB above 10 MHz, LSB below. Convention ensures ║ ║ stations tune to correct frequency automatically. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ FM (Frequency Modulation) ║ ║ ────────────────────────── ║ ║ Bandwidth: 12.5 kHz (narrowband) or 25 kHz (wideband) ║ ║ Emission: G3E (FM telephony) ║ ║ Deviation: ±5 kHz (wideband), ±2.5 kHz (narrowband) ║ ║ Pre-emphasis: 50 µs time constant (standard amateur FM) ║ ║ Sub-audible: CTCSS tones (67-254.1 Hz) for repeater access ║ ║ PL tones: PL (Private Line) = CTCSS. DCS = Digital Coded Squelch ║ ║ Squelch: Carrier-operated squelch + CTCSS/DCS gating ║ ║ Repeater offset: +600 kHz (2m), +1.6 MHz (70cm), varies by band ║ ║ PL access: Transmit CTCSS tone to access repeater ║ ║ Best for: Local comms, repeaters, FM simplex, emergency ║ ║ Calling freqs: 146.520 (2m), 446.000 (70cm) national FM calling ║ ║ Notes: FM has capture effect — stronger signal wins. ║ ║ Better audio quality than SSB for casual use. ║ ║ Wideband = 25 kHz channels, Narrowband = 12.5 kHz. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ AM (Amplitude Modulation) ║ ║ ────────────────────────── ║ ║ Bandwidth: ~6 kHz (3 kHz audio × 2 sidebands) ║ ║ Emission: A3E (full carrier AM) ║ ║ Carrier power: ~33% of total (carrier = 1/3, each sideband = 1/3) ║ ║ Modulation: 100% modulation = carrier swings ±100% ║ ║ Carrier: Full carrier present (not suppressed) ║ ║ Best for: Vintage equipment, nostalgia, AM calling 3.885 MHz ║ ║ Notes: Least efficient mode — carrier consumes power without ║ ║ carrying information. Popular with vintage gear fans. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
Digital Modes — Keyboard-to-Keyboard
╔══════════════════════════════════════════════════════════════════════════════╗ ║ KEYBOARD-TO-KEYBOARD DIGITAL MODES ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ RTTY (Radio Teletype) ║ ║ ────────────────────── ║ ║ Bandwidth: ~300 Hz ║ ║ Emission: F1B (frequency shift keying, telegraphy) ║ ║ Shift: 170 Hz (standard), ±85 Hz from center ║ ║ Baud rates: 45.45 (standard), 50, 75, 100 baud ║ ║ Encoding: Baudot (5-bit) or ASCII (7/8-bit) ║ ║ Speed: ~45 WPM at 45.45 baud ║ ║ Software: MMTTY, Fldigi, N1MM+ ║ ║ Calling freq: 14.070-14.095 MHz (digital sub-band) ║ ║ Notes: Oldest digital mode still in wide use. RTTY contest ║ ║ exchanges are fast. ARRL RTTY contest is major event. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ PSK31 — Real-Time Keyboard Chat ║ ║ ─────────────────────────────── ║ ║ Bandwidth: 31.25 Hz (extremely narrow!) ║ ║ Emission: BPSK (binary phase shift keying) ║ ║ Baud rate: 31.25 baud (one symbol per 32 ms) ║ ║ Speed: ~50 WPM (comparable to fast RTTY) ║ ║ Encoding: Varicode (variable-length character coding) ║ ║ Software: Fldigi, digital master 780, BPSK31 ║ ║ Calling freq: 14.070 MHz (20m), 7.035 MHz (40m) ║ ║ Best for: Ragchewing, keyboard chat, low-power operation ║ ║ Notes: Designed by Peter Martinez G3PLX. Click-to-tune makes ║ ║ it easy to find stations in the passband. Works at very ║ ║ low power — 5W SSB with PSK31 is effective. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ FT8 — The Weak-Signal Revolution (Joe Taylor K1JT) ║ ║ ────────────────────────────────────────────────── ║ ║ Bandwidth: ~50 Hz ║ ║ Emission: 8-tone CPFSK (continuous phase FSK) ║ ║ Tones: 8 tones, 6.25 Hz spacing ║ ║ TX duration: 12.64 seconds per transmission ║ ║ TX cycle: 15 seconds (12.64s TX + 2.36s decode/reply) ║ ║ FEC: LDPC (Low-Density Parity-Check) codes ║ ║ Sensitivity: Works at -21 dB SNR (2500 Hz reference BW) ║ ║ Min SNR: -24 dB with deep LDPC decoding ║ ║ Speed: ~25-30 words per minute (automated exchanges) ║ ║ Software: WSJT-X (standard), JTDX (alternative) ║ ║ Calling freq: 14.074 MHz (20m), 7.074 MHz (40m), etc. ║ ║ Contest: FT-roundup, ARRL contest, WW Digi ║ ║ Notes: Mode name "FT8" = "Franke-Taylor 8-tone". Uses ║ ║ waterfall clicking. Each station takes turns transmitting║ ║ in 15-second slots. Requires PC clock sync (NTP). ║ ║ Can decode signals invisible to the ear. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ FT4 — Fast FT8 for Contesting ║ ║ ──────────────────────────── ║ ║ Bandwidth: ~50 Hz ║ ║ Emission: 4-tone CPFSK (continuous phase FSK) ║ ║ Tones: 4 tones ║ ║ TX duration: 7.5 seconds per transmission ║ ║ TX cycle: ~10 seconds (7.5s TX + 2.5s decode) ║ ║ FEC: LDPC codes ║ ║ Speed: ~2-3× faster than FT8 for exchanges ║ ║ Software: WSJT-X 2.1+ ║ ║ Calling freq: 14.080 MHz (20m) ║ ║ Best for: Multipliers, contests where rate matters ║ ║ Notes: Designed specifically for contesting. Faster exchange ║ ║ rate than FT8, but slightly less sensitive. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ JS8Call — Keyboard-to-Keyboard at Low SNR ║ ║ ──────────────────────────────────────────── ║ ║ Bandwidth: ~50 Hz ║ ║ Emission: Based on FT8 protocol ║ ║ TX duration: Variable (longer than FT8 for text) ║ ║ FEC: LDPC codes (from FT8) ║ ║ Sensitivity: Works at very low SNR (similar to FT8) ║ ║ Software: JS8Call (free, open source) ║ ║ Calling freq: 14.078 MHz (20m), 7.078 MHz (40m) ║ ║ Best for: Keyboard chat when conditions are marginal ║ ║ Notes: "JS8" = Joe Taylor (JT) + Weak Signal + Keyboard. ║ ║ Not a contest mode — for real conversations. ║ ║ Handles callsign-directed messaging like packet radio. ║ ║ Can propagate when SSB is unreadable. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ JT65 — EME/Moonbounce Mode ║ ║ ──────────────────────────── ║ ║ Bandwidth: ~50 Hz ║ ║ Emission: 65-tone MFSK (multiple frequency shift keying) ║ ║ Tones: 65 tones, 2.62 Hz spacing ║ ║ TX duration: 60 seconds per transmission ║ ║ FEC: Forward error correction built-in ║ ║ Sensitivity: Extremely weak — designed for EME (earth-moon-earth) ║ ║ Software: WSJT-X (legacy mode, largely replaced by FT8) ║ ║ Calling freq: 14.076 MHz (20m) ║ ║ Best for: EME, aurora, extremely marginal conditions ║ ║ Notes: Designed by K1JT for moonbounce where signals are ║ ║ 250+ dB below free-space levels. 60-second slots. ║ ║ Largely superseded by FT8 which is faster and similar. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
Digital Voice & Data Modes
╔══════════════════════════════════════════════════════════════════════════════╗ ║ DIGITAL VOICE & DATA MODES ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ Packet Radio (AX.25) ║ ║ ────────────────────── ║ ║ Protocol: AX.25 (amateur version of X.25) ║ ║ Data rate: 1200 baud (VHF via AFSK) or 9600 baud (FSK) ║ ║ Modulation: AFSK (Audio Frequency Shift Keying) at 1200 baud ║ ║ Bell 202 tones: 1200 Hz (mark), 2200 Hz (space) ║ ║ TNC: Terminal Node Controller — modem for packet ║ ║ KISS mode: TNC passes raw frames to host computer ║ ║ AX.25 frame: Flag(7E) + Address(7×2) + Control(1) + PID(1) ║ ║ + Info(0-256) + FCS(2) + Flag(7E) ║ ║ Max info field: 256 bytes per frame ║ ║ Callsigns: AX.25 uses callsign-SSID addressing (e.g., W1AW-7) ║ ║ Best for: BBS, APRS, winlink email, emergency data ║ ║ Notes: The backbone of amateur packet networks. AX.25 ║ ║ v2.2 adds HDLC with SABM/UA/DM connection modes. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ APRS (Automatic Packet Reporting System) ║ ║ ────────────────────────────────────────── ║ ║ Protocol: AX.25 UI frames (connectionless) ║ ║ Data rate: 1200 baud AFSK (Bell 202) ║ ║ US frequency: 144.390 MHz (primary APRS frequency) ║ ║ Alt frequencies: 144.390 MHz (East), 144.390 MHz (Central), ║ ║ 144.390 MHz (West) — all same freq ║ ║ Packet format: TH腮D92!4L"4#P-]... (compressed position) ║ ║ Position report: Lat/Lon/Alt/Speed/Course compressed in base-91 ║ ║ Icon table: / = primary, = alternate (car, house, star, etc.) ║ ║ Objects: Announce events, repeaters, weather spots via APRS-IS ║ ║ Messaging: Two-way APRS text messaging (callsign-SSID directed) ║ ║ Digipeaters: WIDE1-1, WIDE2-1 path (fill-in + wide-area hops) ║ ║ Software: aprs.fi (web), YAAC, APRSISCE/32, aprsdroid (Android) ║ ║ Gateways: I-Gates forward packets to APRS-IS internet network ║ ║ Weather: Automated weather reports from APRS stations ║ ║ Notes: APRS is not just tracking — it's a full tactical ║ ║ information system. Smart beaconing adjusts rate by ║ ║ speed/direction. APRS-IS is the internet backbone. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ D-STAR (Digital Smart Technologies for Amateur Radio) ║ ║ ────────────────────────────────────────────────────── ║ ║ Standard: Icom D-STAR protocol (IC-92, IC-7100, IC-7300, ID-5100) ║ ║ Codec: AMBE+2 (Advanced Multi-Band Excitation) ║ ║ Data rate: 9.6 kbps (voice), 1.2 kbps (data) ║ ║ Voice quality: 3.5 kHz effective audio bandwidth ║ ║ Modulation: GMSK (Gaussian Minimum Shift Keying) ║ ║ Channel width: 12.5 kHz ║ ║ Features: Digital voice + 9.6 kbps data simultaneously ║ ║ Callsign routing (direct callsign-to-callsign) ║ ║ DD mode: 128 kbps data (slow, but full IP capability) ║ ║ Network: D-STAR reflectors, DCS rooms, DPlus amplifiers ║ ║ Gateway: D-STAR gateway connects repeaters to internet ║ ║ Software: DPlus, DExtra, D-STAR Dashboard (ircDDB) ║ ║ Notes: First major amateur digital voice mode (2004). ║ ║ AMBE+2 codec is proprietary (DVSI patent). ║ ║ D-STAR voice quality is often criticized vs analog FM. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ DMR (Digital Mobile Radio) ║ ║ ────────────────────────── ║ ║ Standard: ETSI TS 102 361 (DMR Tier I/II/III) ║ ║ Codec: AMBE+2 (same as D-STAR) ║ ║ Modulation: 4FSK (4-level Frequency Shift Keying) ║ ║ Data rate: 9.6 kbps voice per slot ║ ║ Channel width: 12.5 kHz (two 6.25 kHz-equivalent slots) ║ ║ TDMA: 2-slot TDMA — two simultaneous QSOs per channel ║ ║ Time slots: TS1 and TS2 (30 ms frame, 15 ms per slot) ║ ║ Color code: 0-15 (analogous to CTCSS PL tones) ║ ║ Talkgroups: 1-9999 (group call addressing) ║ ║ Network: Brandmeister, TGIF, FreeDMR, DMR-MARC ║ ║ Hotspots: Pi-Star, MMDVM (Multi-Mode Digital Voice Modem) ║ ║ Software: CPS (code plug programmer), Brandmeister dashboard ║ ║ Notes: TDMA gives 2× channel capacity vs D-STAR. ║ ║ Code plug programming is complex. Talkgroup routing ║ ║ can be confusing for newcomers. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ System Fusion (Yaesu) ║ ║ ────────────────────── ║ ║ Standard: Yaesu System Fusion (YSF) ║ ║ Codec: AMBE+2 (same as D-STAR/DMR) ║ ║ Modulation: C4FM (Continuous 4-level FM) ║ ║ Channel width: 12.5 kHz ║ ║ Data rate: 9.6 kbps voice ║ ║ Features: Wires-X (Yaesu Internet Gateway System) ║ ║ YSF Reflectors (linked repeaters worldwide) ║ ║ VW mode: Voice + Data simultaneously ║ ║ DG-ID (Digital Group ID, 00-99) ║ ║ Network: YSF reflectors, WIRES-X rooms, FCS rooms ║ ║ Software: WIRES-X software, YSF reflectors dashboard ║ ║ Notes: Yaesu's answer to D-STAR/DMR. C4FM is simpler than ║ ║ DMR's TDMA but uses more bandwidth. Good voice quality. ║ ║ ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ M17 — Open-Source Digital Voice ║ ║ ────────────────────────────── ║ ║ Standard: Open-source digital voice protocol ║ ║ Codec: Codec2 (open source, no patent encumbrance) ║ ║ Modulation: 4FSK ║ ║ Data rate: 9.6 kbps ║ ║ Channel width: 12.5 kHz ║ ║ Features: Fully open-source, IP-based routing ║ ║ Software: M17 project (m17project.org) ║ ║ Notes: The "free software" alternative to proprietary digital ║ ║ voice modes. Codec2 gives comparable quality to AMBE+2. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
How to Get Started in Ham Radio
Getting started in ham radio requires passing an FCC exam, acquiring equipment, and learning operating practices. The barrier to entry is low — you can be on the air for under $50 with a handheld radio.
Step 1: Study for the Technician Exam
The Technician exam (Element 2) is 35 multiple-choice questions drawn from a publicly available pool of 386 questions. Passing score: 26/35 (74%).
- HamStudy.org — Free online practice exams (most popular resource)
- ARRL Ham Radio License Manual — Comprehensive textbook for Technician class
- KB6NU's No-Nonsense Study Guide — Concise, exam-focused review
- HamExam.org — Additional practice test generator
- Local clubs — Many offer free 1-day Technician classes
Key topics: electrical safety, Ohm's law, radio wave propagation, antenna basics, FCC regulations (Part 97), operating procedures, band plans, digital modes, and emergency communications.
Step 2: Take the Exam
- VEC (Volunteer Examiner Coordinators): ARRL VEC, W5YI VEC, Laurel VEC
- Exam fee: $15 (typically, may vary by VEC)
- Required ID: Government-issued photo ID
- No prerequisites: You can walk in cold — no class required
- Results: FCC issues FCC Registration Number (FRN) and license
- Call sign: Assigned after license granted (check FCC ULS database)
Step 3: Get Equipment
╔══════════════════════════════════════════════════════════════════════════════╗ ║ EQUIPMENT RECOMMENDATIONS ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ VHF/UHF HANDHELD (HT) — First Radio ║ ║ ────────────────────────────────────── ║ ║ Budget: Baofeng UV-5R .............. $25-35 ║ ║ Woxsun UV-5R equivalent .... $25-35 ║ ║ Mid-range: Yaesu FT-65R .............. $90 ║ ║ Kenwood TH-D75A ............ $500 ║ ║ Notes: UV-5R is cheap but has front-end overload issues. ║ ║ For serious use, Yaesu/Kenwood/Icom are better. ║ ║ Repeater programming requires CHIRP software (free). ║ ║ ║ ║ VHF/UHF MOBILE — For the Car/Base ║ ║ ──────────────────────────────────── ║ ║ Budget: Anytone AT-5888UV ......... $100-150 ║ ║ Mid-range: Yaesu FT-8900R ............ $300 ║ ║ Kenwood TM-D710G .......... $400 ║ ║ Notes: 50W on 2m, 45W on 70cm. Requires power supply + antenna. ║ ║ ║ ║ HF BASE STATION — The Big Leap ║ ║ ──────────────────────────────── ║ ║ Entry: Xiegu G90 ................ $450 (QRP, 20W, built-in tuner) ║ ║ Mid-range: Icom IC-7300 ............. $1,100 (SDR, 100W, spectrum scope)║ ║ High-end: Yaesu FTDX10 ............ $1,500 (dual-receiver, excellent) ║ ║ Icom IC-7610 ............. $4,000 (dual-BAND SDR, flagship) ║ ║ Notes: IC-7300 is the gold standard for new HF operators. ║ ║ Direct-sampling SDR architecture. Built-in USB sound card. ║ ║ Spectrum scope lets you SEE the band. ║ ║ ║ ║ QRP (LOW POWER) — For the Adventurous ║ ║ ────────────────────────────────────── ║ ║ Budget: QRP Labs QMX ............. $65 (5W, CW/Digital, kit) ║ ║ Mid-range: Elecraft KX2 ............. $1,000 (8W, CW/SSB/Digital) ║ ║ High-end: Elecraft KX3 ............. $1,500 (15W, full-featured) ║ ║ Notes: QRP = 5W or less. Requires skill in CW/digital modes. ║ ║ "QRP" = "reduce power" in Q-code. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
Step 4: Antenna Basics
The antenna is often more important than the radio. A mediocre radio with a great antenna outperforms a great radio with a mediocre antenna.
╔══════════════════════════════════════════════════════════════════════════════╗ ║ ANTENNA FUNDAMENTALS ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ DIPOLE (Half-Wave) ║ ║ ───────────────── ║ ║ Formula: Length (ft) = 468 / Frequency (MHz) ║ ║ Example: 40m dipole: 468 / 7.1 = 65.9 ft (each leg = 32.95 ft) ║ ║ 20m dipole: 468 / 14.1 = 33.2 ft (each leg = 16.6 ft) ║ ║ 2m dipole: 468 / 146 = 3.2 ft (each leg = 1.6 ft) ║ ║ Gain: 2.15 dBi (unity gain reference) ║ ║ Impedance: ~73 Ω (resonant at design frequency) ║ ║ Feedpoint: Center-fed with 50Ω coax (SWR ≈ 1.5:1) ║ ║ Pattern: Toroidal — radiates broadside to wire ║ ║ Notes: Cheapest antenna. Can be strung between trees/poles. ║ ║ Use 1:1 balun at feedpoint to prevent coax common-mode. ║ ║ ║ ║ VERTICAL (Quarter-Wave) ║ ║ ─────────────────────── ║ ║ Formula: Length (ft) = 234 / Frequency (MHz) ║ ║ Example: 20m vertical: 234 / 14.1 = 16.6 ft ║ ║ 2m vertical: 234 / 146 = 1.6 ft ║ ║ Gain: 0 dBi (no gain, omnidirectional) ║ ║ Impedance: ~36 Ω (requires ground radials or tuner) ║ ║ Radials: 16+ radials, each λ/4 long = best ground system ║ ║ Pattern: Omnidirectional — radiates equally in all horizontal dirs ║ ║ Notes: Good for DX (low angle radiation). Needs good ground. ║ ║ Hamstick verticals are compact mobile option. ║ ║ ║ ║ YAGI (Directional Beam) ║ ║ ──────────────────────── ║ ║ Elements: Director(s) + Driven element + Reflector(s) ║ ║ Gain: 6-15 dBi depending on number of elements ║ ║ F/B ratio: 15-30 dB (front-to-back rejection) ║ ║ Beamwidth: 30-90° (depends on elements) ║ ║ Example: 3-element 20m Yagi: 36 ft boom, 8 dBi gain ║ ║ 5-element 15m Yagi: 24 ft boom, 11 dBi gain ║ ║ Notes: Must be rotatable for DX. Requires mast + rotator. ║ ║ Stacking multiple Yagis adds 3 dB per doubling. ║ ║ ║ ║ MLOOP (Magnetic Loop) ║ ║ ───────────────────── ║ ║ Size: ~λ/10 circumference (1/3 wavelength diameter) ║ ║ Example: 20m magnetic loop: 20 ft diameter ║ ║ Gain: -3 to 0 dBi (lossy but compact) ║ ║ Bandwidth: Very narrow — requires retuning for each frequency ║ ║ Notes: Best compact HF antenna. Good for apartments/small lots. ║ ║ High Q = narrow bandwidth. Great for RX in noisy locations. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
Propagation Mechanisms
Understanding propagation is essential for effective ham radio operation. Different frequency ranges rely on different physical mechanisms to travel beyond line-of-sight.
HF Propagation
- Ground Wave: Follows the Earth's surface. Range depends on frequency, power, and ground conductivity. Useful up to ~100 miles on MF/HF.
- Skywave (F-Layer Skip): Signals refract off the F-layer ionosphere (150-800 km altitude). Enables worldwide communication. Skip distance: 200-3000+ miles depending on angle.
- NVIS (Near Vertical Incidence): Signals sent nearly straight up reflect back down within ~300 miles. Used for regional HF communication. Best on 40m and 80m during daytime.
- Multi-hop: Signals bounce between ionosphere and ground multiple times for intercontinental paths.
- Sporadic E: Unpredictable E-layer ionization patches. Enables 6m DX (50 MHz) over 1000+ miles.
- Auroral propagation: Signals scatter off aurora borealis. Allows VHF DX during geomagnetic storms.
- Transequatorial (TEP): Propagation across the equator via guided ionospheric modes. Affects 6m-10m between Southern US and South America.
VHF/UHF Propagation
- Line-of-Sight (LOS): Primary VHF/UHF mode. Range limited by horizon (~10-60 miles depending on antenna height). Free-space loss increases with frequency.
- Tropospheric Ducting: Temperature inversions create waveguides in the troposphere. 6m, 2m, 70cm signals duct for hundreds of miles over water.
- Sporadic E (6m): The "Magic Band" phenomenon. E-layer ionization clouds enable 1000+ mile contacts on 50 MHz. Peaks in May-June and November-December.
- Meteor Scatter: Signals reflect off ionized meteor trails. Enables 2m and 6m DX during meteor showers. Contact times: 1-10 seconds per burst.
- EME (Earth-Moon-Earth): Signals reflect off the Moon's surface. ~250 dB path loss. Requires 1000W+, high-gain antennas, and digital modes (JT65/FT8). Maximum distance: ~480,000 miles round-trip.
- Rain Scatter: Signals scatter off heavy precipitation cells. Useful on 10 GHz+ for microwave DX.
Solar Cycle Impact
The 11-year solar cycle dramatically affects HF propagation. Key indices:
╔══════════════════════════════════════════════════════════════════════════════╗ ║ SOLAR CYCLE & PROPAGATION ║ ╠══════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ SUNSPOT NUMBER (SSN) — 0-300+ ║ ║ ──────────────────────────── ║ ║ Minimum (SSN < 20): 10m dead, 15m marginal, 20m good at night ║ ║ 40m & 80m best for DX. NVIS works well. ║ ║ Maximum (SSN > 100): 10m wide open, 15m excellent, 20m全天候 ║ ║ All HF bands propagate worldwide. ║ ║ Higher MUF = higher frequencies usable. ║ ║ ║ ║ SOLAR FLUX INDEX (SFI) — Measure of 10.7 cm solar radio emission ║ ║ ───────────────────────────────────────────────────────────── ║ ║ 65-70: Solar minimum conditions ║ ║ 100-150: Moderate solar activity ║ ║ 200+: Strong solar activity, enhanced propagation ║ ║ 300+: Extreme events (rare), potential radio blackouts ║ ║ ║ ║ K-INDEX (Geomagnetic Activity) — 0-9 ║ ║ ──────────────────────────────────── ║ ║ 0-2: Quiet conditions, stable propagation ║ ║ 3-4: Unsettled — marginal HF conditions ║ ║ 5-6: Minor storm — degraded HF, aurora possible ║ ║ 7-9: Major storm — HF blackouts, aurora visible mid-latitudes ║ ║ Aurora scatter enables VHF DX on 6m/2m. ║ ║ ║ ║ MUF (Maximum Usable Frequency) ║ ║ ─────────────────────────────── ║ ║ MUF = highest frequency that will reflect from ionosphere. ║ ║ Below MUF: skywave works. Above MUF: signal escapes to space. ║ ║ MUF varies: solar max > solar min; daytime > nighttime; summer > winter. ║ ║ Typical MUF: 5-30 MHz (varies wildly with conditions). ║ ║ ║ ║ FOBS (Frequency of Best Signal) ║ ║ ──────────────────────────────── ║ ║ FOT = 0.85 × MUF — most reliable frequency for DX. ║ ║ Use real-time propagation tools: DX Toolbox, WSPR, PSKReporter. ║ ║ ║ ╚══════════════════════════════════════════════════════════════════════════════╝
Propagation Tools & Resources
- VOACAP: HF propagation prediction (voacap.com) — ITU model
- DX Toolbox: Real-time solar indices, SFI, K-index, A-index
- PSKReporter: See who's hearing your signal in real-time (pskreporter.info)
- WSPR: Weak Signal Propagation Reporter — beacon network maps propagation
- DXMaps: Real-time DX cluster and propagation map
- SolarHam.com: Live solar data, SFI, K-index, X-ray flux
- ARRL Propagation Forecast: Weekly forecast by band
- HamCAP: HF propagation prediction software by K1CT
Emergency Communications (EmComm)
Ham radio's most important function is providing communications when all other systems fail. ARES (Amateur Radio Emergency Service) and RACES (Radio Amateur Civil Emergency Service) coordinate volunteer operators.
- National Calling Frequency: 146.520 MHz (2m FM) — monitored by all emcomm ops
- Local EmComm Nets: Check into your local ARES/RACES net for training
- FEMA Regions: Each region has ARRL Section-level emcomm coordinators
- ARES/RACES: Formal volunteer organizations coordinated with government agencies
- Winlink: Email-over-radio via packet/Winlink — works when internet is down
- Go-Kit: Portable station: HT + spare batteries + charger + logbook + antenna
Timeline
1912Radio Act of 1912First US radio regulation; requires licenses for all radio operators
1914ARRL FoundedHiram Percy Maxim establishes American Radio Relay League
1917WWI SuspensionAmateur radio silenced; equipment seized for military use
1923First Transatlantic Amateur ContactPaul Godley (2ZE) and French amateurs span the Atlantic on 200m
1927Federal Radio ActFCC precursor regulates all US radio, including amateur allocations
1929W1AW FoundedARRL headquarters station begins transmitting from Hartford, CT
1935New England HurricaneHams provide sole communications for devastated coastal areas
1940WWII BeginsAmateur radio suspended again; hams serve in military signals units
1945Post-War RevivalPent-up demand triggers massive growth; VHF experimentation begins
1948FM Repeater EraFirst amateur repeaters establish local FM networks
1953UHF Allocations440 MHz band opened for amateur use
1961OSCAR-1 LaunchFirst amateur satellite enters orbit; space communications begin
1964FT-8 (concept)K1JT begins work on weak-signal digital modes (released 2017)
1977Morse Code DroppedFCC no longer requires CW proficiency for any license class
1991NOAA 60m Band5 MHz shared channels allocated for emergency use
2007FT8 ReleasedJoe Taylor K1JT releases FT8 — revolutionizes weak-signal DXing
2017Technician HF PrivilegesFCC expands Technician HF privileges to 80m-10m (limited)
20202200m & 630mLF/MF bands (136 kHz, 472 kHz) formally allocated to amateurs